Enzymes when exposed to certain chemicals, are prone to denaturing or inactivation. In particular, U.S. Pat. No. 6,017,866 states that: “Important stability problem is the sensitivity of enzymes towards denaturation by anionic, cationic or nonionic surfactant molecules”.
On the other hand, some enzymes, as e.g. lipases, are activated by certain surfactants [Lipase Activation by Nonionic Detergents. Juan Hermoso, et al., (1996) J. Biol. Chem, v. 271, pp. 18007-18016], while anionic surfactants, proved to be inhibitory [Enhanced ethyl butyrate production by surfactant coated lipase immobilized on silica. Amit Thakar, et al. (2005) Process Biochemistry, v. 40(10) pp. 3263-3266; Effect of nonionic surfactants on Rhizopus homothallicus lipase activity. A comparative kinetic study. J. C. Mateos Diaz, et al. Molecular Biotechnology, v. 35(3), pp. 205-214; Isolation and properties of extracellular lipase of native (B-10) and mutant (M-1) Serratia marcescens strains]. Duzhak A B, et al. (2000) Prikl Biokhim Mikrobiol. v. 36(4), pp. 402-11; Increased activity of Chromobacterium viscosum lipase in aerosol OT reverse micelles in the presence of nonionic surfactants. Yasushi Yamada, et al. (1993) Biotechnol. Prog., v. 9(5), pp 468-472; Effect of Surfactants and Polyethylene Glycol on the Activity and Stability of a Lipase from Oilseeds of Pachira aquatica. Patricia Peres Polizelli, et al., J. Amer. Oil Chem. Soc. v. 85(8), pp. 749-753]. Lipases are used in a number of industries and applications: laundry, dishes, hard surface cleaning, wastewater treatment, water or soil remediation, industrial applications, enhanced oil recovery, textile processing, agricultural chemicals, flavor industry, biocatalytic resolution of pharmaceuticals, production and processing of esters and amino acid derivatives, cosmetics, and skin and hair care applications.
Enzymes have been used for cleaning in industrial applications. U.S. Pat. No. 4,169,817 teaches that, “ . . . the enzyme-containing liquid detergent composition has a particular and important use in cleaning semi-permeable membranes used in reverse osmosis processes. The membranes are generally composed of cellulose acetate, and the detergent composition can be utilized in a clean-in-place operation to remove clogged material from the pores of the membrane.” U.S. Pat. No. 7,165,561 discloses methods to clean fouled cross-flow membrane systems, including reverse osmosis.
When enzymes are used in detergent formulations, surfactants have to be chosen carefully as it has been found that, e.g., nonionic surfactants can reduce the effectiveness of certain enzymes: “Nonionic surfactants seem to prevent or delay enzyme penetration at the interface, thereby decreasing lipase activity.” (Jurado, 4) It has been shown, as in U.S. Pat. No. 7,645,730, that compounds from the yeast extracts bind with surfactants and these combinations displayed increased surface activity towards oil, other hydrophobic organic substrates and some odorous substances.
U.S. Pat. No. 6,071,356 discloses the combination of lipase and protease for cleaning in place for industrial equipment, including membranes, mostly in food processing industries, and by using enzymes the amount of water and surfactants can be reduced.
Cellulase hydrolyzes celluloses and cellulolytic enzymes are used in a number of industrial and consumer products. For example, the addition of cellulase into detergent formulations has been shown to improve their efficacy. However, U.S. Pat. No. 5,833,066 teaches that: “ . . . in anionic surfactant liquid detergent compositions the stability of enzymes, in particular cellulases is greatly reduced.”
Cellulases are also used in fabric treatment to create the “stone washed” look of denim, de-inking of fabrics, and removing fuzz from cotton fabrics. They are also used to prevent clogging of ink in print heads, U.S. Pat. No. 7,156,514 (Rosa), de-inking of waste paper, in glucose production by enzymatic action on cellulosics and other uses.